During the student's day demonstrations last week an Iranian student named Majid Tavakoli was arrested by the authorities after giving a rousing pro-democracy speech. The next day, government newspapers published photographs of him dressed in a full hijab – with chador and headscarves, as typically worn by more devout adherents to the Islamic dress code that is mandatory for women Iran. There is a dispute about the authenticity of the image; whether it was photoshopped or whether he was forced to wear women's clothes by his captors.

Either way the pictures were meant to humiliate Tavakoli, and by extension the green movement. The publication of such pictures has a specific meaning in the vernacular of Iranian politics, drawn from historic precedence. In July 1981, the then disgraced president, Banisadr, was alleged to have escaped from the country dressed as a woman. Whether true or not, he was certainly photographed on his arrival in Paris minus his signature moustache.

In street slang the image of a man dressed as woman is a slanderous of his sexuality and essential manhood. In political terms, evoking Banisadr represents a sort of political red card. The conservative and pro-government press has in recent weeks threatened the leaders of the green movement several times with the same fate as the deposed first president of the state. Banisadr, once a trusted lieutenant of Ayatollah Khomeini, swept to power in the first elections with a massive popular mandate. He seriously overestimated his support base by engaging in a power struggle with the Ayatollah and went from being at the heart of the system to pariah status. The message to messrs Mousavi, Khatami and Karroubi (the steadfast and so-far united leaders of the green movement) is clear; do not confuse popularity with power – it is the system that has bestowed power upon you and in defying it you are close to being beyond the pale.

So, the gentlemen in charge of the propaganda war against the opposition know their history well. But they are no good at sociology.

Within hours of Tavakoli's photograph being published in the newspapers, hundreds of young Iranian men posted photographs of themselves dressed in headscarves, bed sheets and other forms of improvised hijab. This has spread online in chat rooms and websites and soon enough to the meetings of the opposition.

The message sent back to the men in charge in Iran is an invitation to wake up and smell the coffee. The contemporary opponents of the regime are not hampered by the symbolic language of oppression. They are taking ownership of it as a step towards dismantling the very architecture of the system of oppression. The green movement is a post-modern, post -ideological civic movement. It also points to how far the notion of women as a political force has travelled in the 30 years since the revolution. Women are at the forefront of this movement and its badge of honour – they are not an accessory. Zahra Rahnavard and Shirin Ebadi are key leaders and spokeswomen of the movement and Neda its most famous martyr. The green movement is helping to redefine the idea of womanhood in the language of a contemporary Iran. As a leading Iranian website and chat room exhorts, "Be a man. Send us your picture as a woman".